General and Specific Aims: The general aim of this study is to explore the effects of prenatal stress on calming in infants born with Clifford's postmaturity syndrome. Specifically, the proposed experiments are designed to address the following questions: l) Do postmature infants have elevated postnatal B-endorphin and ACTH levels compared to term infants, and, if so, will the stage of Clifford's syndrome at which s/he has been diagnosed, correspond with the degree of elevation of the physiological measures? 2) Will B-endorphin a ACTH levels at birth predict (negatively) the ability of a sweet stimulus to calm irritable postmature infants? 3) Do postmature and healthy term infants differ in their calming responses to intraoral tactile stimulation via a pacifier? The proposed study is comprised of two experiments. In Experiment l, infants will be assigned to either one of three conditions: infants receiving sucrose will be given a 0.1 ml aliquot of either a 14% or 24% sucrose solution (weight/volume) delivered for 10 sec, once/min, over a 5- minute period. The same protocol will be used to administer sterile water to infants assigned to the water condition. Infants in Experiment 2 will receive a blank pacifier for 15 minutes. The dependent variables will be time spent crying during the test phases (stimulation and poststimulation), and B-endorphin and ACTH levels at birth. Long-Term Objectives: It is expected that these findings will increase our understanding of processes underlying oral events and their relationship to affective states in human neonates. In addition to expanding our knowledge of the mechanisms mediating calming in healthy human infants, these findings will also provide information regarding infants born with Clifford's postmaturity syndrome. Furthermore, such findings would predict diminished reactivity to sucrose in opiate-tolerant and other prenatally stressed infants and would serve as the basis for recommendation of interventions.